Kerker Pipes

[egleaves]

I just bought a 1980 eleven special, with Kerker pipes. I can't find any info on these pipes anywhere. Has anyone ever used these pipes on their bike? What advantage, if any, do they give over stock pipes?

[Jerry]

The Kerker pipes are considered to be amoung the better performance pipes on the market. As with all 4 into 1 systems, you loose the weight of the 2nd muffler and gain some ground clearance. Generally the carbs need to be re-jetted to take advantage of the scavaging and higher-end flow of the system. Check your plugs for color to make sure the PO did the job right. Typically the Kerker improved mid and top-end performace at a slight loss of low-end grunt. Performance also will vary depending on which muffler you use. The sound is also different than a 4 into 2 system.

Drawbacks include - on some models - restricted access to the oil filter and inability to use the center stand, which must be removed to install the exhaust system.

The Kerker is a good system, particularly if the carb jetting has been set to match.

[egleaves]

Thanks for the info. I do seem to be lacking a little bit of low end power, but once it hits the powerband, we're off! I read somewhere else about the center stand needing to be removed, but mine is on the bike and works just fine. As soon as I get a chance I'll have to check out the plugs. I was told the carbs were re-worked right before I bought it, we'll see.

[mraaaaaaaaaa]

Kerker Pipes

Was about to post Myself about the Kerkers.

Still restoring My 78E.

Yesterday pulled the pipes, no problem gettin them off,

downtubes not even clamped to the muffler. LOL

reason for the removal, black paint, probably primer,

burned off after 50 miles or so of My initial testing/tuning, etc..

Found a baffle attached to the end of the tubes, which,

supported the muffler, except for the back muffler bolt, LOL

Oh yeah, looked through muffler, and, no baffles, just the tube

and coned at the end with KERKER stamped on em, LOL !

So, My question is, does anyone know if that is enough

back pressure?

Still feeling out the scoots ability, does kinda have the low

end lug, 0 to 40 about 2 seconds, then, she really cranks,

hit 2nd at about60 or so, & she pulls very good, did not lift up

front though, so, like I was saying, still trying to figure out

what to do.

On My carb cleaning adventure, I did write down the different

settings/sizes, and here they are;

Floats=25.7mm

Main Jet=#137.5

Jet Needle=5GZ6/3

Needle Jet=X-2

Starter Jet=#40

Pilot Jet=#42.5

Fuel Valve Seat=2.0mm (.079)

Idle Mix Turn Screw=1 3/4 (approx.)

Idle Turn Screw=5 1/4 (1450 rpms) (for now) lol

Plugs nice and tan=7s

So, should I look fer a baffle, or what ???????

Thanks for Your X !!! Andy B. Keepda back rubber down !!

[TopCatGr58]

Hey there Andy,

I copied this thread from the Product Eval Forum to here, because the Product Eval is more for providing experience, opinions about products folks have gotten and used. Yours and EGLeaves posts are more requests for help, and so you'll get more responses here!

You state MPH, but what rpm and gear are you getting up to 40mph and feel it's lugging?

The 4-1 pipes as has been stated are more for mid/higher rpm power band, so it's a bit normal to not have as much grunt in the lower rpms, but possibly worse since you have no baffle on your muffler???

You have what sounds like good plug color, but is this color from the upper driving rpms, or more due to the idle circuit? Does it pull to redline in 4th, or does it feel like it's falling on it's face?? Also, can't remember and you didn't state here whether Airbox or Indy Filters?

I ran 4-1 pipes with the Stock Airbox for years without rejetting, but that was in my ignorant youth! Mine did have a simple baffle, just a foot long louvered pipe in the middle of the cone! Without a baffle it may be too lean?? When I did my rebuild and added Indy filters, I then rejetted 3 sizes up, and could probably go another one.

Hopefully someone with more carb tuning experience will chime in?
T.C.

[mraaaaaaaaaa]

Kerker Pipes

Thx TC,

Stock airbox, noticed 2 holes on bottem of box

located between the rear 2 wing nuts.

Iam assuming this is a drill out, or, is it stock ??

Today, drillin out the # 3 inside exhaust stud, its busted off

even with flange. Also yesterday p/u new gaskets.

#3 gasket fell right out, mayb this is y it sounded like

I lit off a string of "Lady Fingers" on downshift from

2nd to 1st, lol. FUN FUN FUN, the other gaskets look

like they r stock !!! Might just put in new on top of old.

Also, draind oil for the 3rd X yesterday, still deciding

on what to put in this X, probably the valvoline 4 stroke

motorcycle again.

Think Ill stop for now, will post after I get it back out,

and try a few redlines.

Oh,whats the best way for the throttle chop, for the

plug read ??

Thx, & keep da back rubber down !! Andy B.

[beegshot]

Got one, like it...

I have a Kerker 4 into 1 on my XJ. I have no center stand and I have to remove the pipe to change the oil. But, I always clean, polish, and wax the pipe at every oil change. The center stand lives in my paint cabinet and is installed for maintenance (the rear support for the pipe must be loosened so the center stand bolts can be temporarily installed). It makes the oil change a little (alright, a lot) more laborious. When I bought it (the Kerker pipe) I could not afford a stock replacement for my broken pipes. I like the sound and have had zero carb tuning issues. My $0.02

Robert

edit: corrected smelling errors.

[Pain]

i have a Kerker on my 80 special, and really like the sound.

However, I also still have a center stand, and don't have to pull the pipes to change my filter (though it does take some fiddling).

Guess I got lucky.

[79XS11F]

The Kerker pipe I had on my bike in 1980 also had no baffle wadding. Just a long perforated tube that was attached to the baffle end . It went into the baffle all the way down to the collector.
Was a GREAT pipe and NOTHING sounds as sweet as a kerker on a tuned bike
Rob

[egleaves]

I took a closer look today, and found that my Kerker pipe is keeping my center stand down just a bit. I haven't had any clearance issues, yet, but I might take the stand off just in case.

[TopCatGr58]

Hey Andy,

Hope you've found the techique in a search by now, but if not, what folks have said is to get new plugs, find a modest inclined road, and have it in a gear that you can maintain about 2/3's throttle, run it for about a minute at that, then hit the kill switch, pull in the clutch, close the throttle, and coast to a stop, pull the plugs and inspect.

It's also been stated that due to the lack of lead and such in modern fuels, that gauging by the insulator isn't as accurate, but you should look at the base of the grounding prong/ring on the bottom of the plug, a light grey/black film on it is okay, but thicker flaky sooty is too rich. I believe PGGG also posted some photos or links to them. WE have a plug reading tip, but it is with the older fuel information, but it still does apply fairly well.

Other Gurus feel free to chime in here with any other tips, corrections, etc.!
T.C.